This guide was prepared by
the Office of the Secretary of Defense (OSD) Cost Analysis Improvement
Group (CAIG) for use by Department of Defense (DoD) components
in developing estimates of weapon operating and support (O&S)
costs. This guide supersedes previous O&S CAIG guides, and
should be considered the authoritative source document for preparing
O&S cost estimates.

There has been an increased
emphasis on operating and support costs in recent years. Independent
review and validation of O&S estimates is critical to informed
decisionmaking on major systems that will require the commitment
of O&S funds for many years into the future.

This guide implements several
DoD instructions and directives that are further explained in
Chapter 1. It should be used to prepare O&S cost estimates
for systems that will be reviewed by the CAIG. The guide also
may be used to develop O&S estimates for weapon systems reviewed
outside the Defense Acquisition Board (DAB) process. General guidelines
for preparing and documenting O&S estimates are provided in
Chapters 3 through 6. Cost element structures and definitions
for various categories of major weapon systems are presented in
the appendices.